# Digoxin: veterinary dose and monograph

> Digoxin is a veterinary cardiovascular drug. Cardiac glycoside — a positive inotrope and, more importantly, a negative chronotrope that slows AV conduction via increased vagal tone. Indications include rate control of atrial fibrillation / supraventricular tachyarrhythmia; adjunct in selected dilated cardiomyopathy / CHF. This monograph lists 6 reference doses for dogs, cats, horses and ferrets, each with route, frequency and source.

Source: https://vetmasterji.com/drugs/digoxin · Last reviewed: 2026-10-01

## At a glance

- **Drug class:** Cardiovascular
- **Also known as:** Lanoxin, Cardoxin
- **Species with doses:** Dogs, Cats, Horses and Ferrets
- **General dose range:** 0.003–0.011 mg/kg PO q12h (dog) / q48h (cat) — check the species tables for the indication
- **Routes:** PO, IV
- **Last reviewed:** 1 October 2026

## Indications

- Rate control of atrial fibrillation / supraventricular tachyarrhythmia
- Adjunct in selected dilated cardiomyopathy / CHF

## Digoxin dose by species

Doses are per administration unless stated. mg/kg doses scale with body weight; per-animal, per-quarter and infusion-rate doses are shown as the reference writes them.

### Dogs

*Digoxin doses for dogs*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| AF rate control / CHF (oral maintenance) | 0.003–0.005 mg/kg | PO | q12h | — |
| Rapid digitalization (IV — inpatient only) | 0.0055–0.011 mg/kg | IV | q1h to effect | — |

- AF rate control / CHF (oral maintenance): Dose on LEAN body weight. Papich 5e: 0.005–0.011 mg/kg q12h PO (dogs >20 kg: 0.22 mg/m² q12h; subtract 10% for elixir); atrial fibrillation 0.005 mg/kg q12h, may be combined with diltiazem 3 mg/kg q12h. Plumb’s p.402: AF 0.003–0.005 mg/kg q12h (Hogan 2004) or 0.005–0.0075 mg/kg q12h (Keene & Bonagura 2009); DCM 0.0025 mg/kg q12h. Trough 0.8–1.2 ng/mL, 3–5 days after starting.
- Rapid digitalization (IV — inpatient only): Papich 5th ed: "Rapid digitalization: 0.0055–0.011 mg/kg q1h IV to effect." ⚠ ECG monitoring is mandatory — the therapeutic index is narrow and IV loading is the highest-risk way to give digoxin. Reserve for hospitalised patients; oral maintenance above is the usual route.

### Cats

*Digoxin doses for cats*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| DCM / advanced AV-valve disease (not HCM) | 0.007–0.01 mg/kg | PO | q48h | — |

- DCM / advanced AV-valve disease (not HCM): Papich 5e: 0.008–0.01 mg/kg q48h PO (about ¼ of a 0.125 mg tablet per cat). Plumb’s p.402 (Ware & Keene 2000): 0.007 mg/kg PO every other day on lean weight; level at 10+ days, 8–10 h post-dose, target 1–2 ng/mL. Generally contraindicated in feline hypertrophic cardiomyopathy. Tablets are better tolerated than the alcohol elixir.

### Horses

*Digoxin doses for horses*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Atrial fibrillation rate control / CHF | 0.011–0.015 mg/kg | PO | q12h | — |
| IV maintenance | 0.002–0.0022 mg/kg | IV | q12h | — |

- Atrial fibrillation rate control / CHF: Plumb’s p.402 (Mogg 1999): maintenance 11 µg/kg PO q12h (loading 44 µg/kg PO or 11 µg/kg IV slowly); keep plasma 0.5–2 ng/mL. Papich 5e: 15 µg/kg q12h PO or 2 µg/kg IV q12h. Monitor serum digoxin and potassium. ARCI Class 4.
- IV maintenance: Papich 5e: 2 µg/kg IV q12h. Plumb’s p.402 (Mogg 1999): 2.2 µg/kg IV q12h. Narrow therapeutic index — monitor levels and ECG.

### Ferrets

*Digoxin doses for ferrets*

| Indication | Dose | Route | Frequency | Duration |
| --- | --- | --- | --- | --- |
| Dilated cardiomyopathy | 0.005–0.01 mg/kg | PO | q12–24h | — |

- Dilated cardiomyopathy: Plumb’s p.402: 0.005–0.01 mg/kg PO once to twice daily using the elixir (Williams 2000); 0.01 mg/kg once daily initially, may increase to twice daily (Hoeffer 2000). Monitor as in dogs and cats.

## Contraindications

Ventricular arrhythmias, AV block, hypertrophic cardiomyopathy with outflow obstruction, hypokalaemia, significant renal impairment (renal excretion). Avoid loading doses.

## Adverse effects

- Anorexia, vomiting, diarrhoea — often the FIRST signs of toxicity
- Arrhythmias of any type — AV block, VPCs, bradycardia
- Lethargy, depression

## Drug interactions

- NARROW THERAPEUTIC INDEX — Plumb's advises enhanced monitoring whenever any of the drugs below (or others in the same class) are added to a patient stabilised on digoxin
- May REDUCE digoxin levels: aminosalicylic acid, antacids, chloramphenicol (dogs), cholestyramine, cimetidine, metoclopramide, oral neomycin, phenobarbital, St John's wort, sucralfate, sulfasalazine, penicillamine
- May RAISE levels / slow elimination / enhance toxicity: amiodarone, anticholinergics, ACE inhibitors (captopril and others), coleus, cyclosporine, diazepam, diltiazem (data conflict), erythromycin, furosemide, hawthorn, ketoconazole, itraconazole, omeprazole and other PPIs, quinidine, reserpine, succinylcholine, tetracycline, verapamil
- Quinidine specifically: the rule of thumb is to DECREASE the digoxin dose by 50% if used together
- Beta-blockers: additive negative effects on AV conduction — complete heart block is possible
- Calcium-channel blockers (diltiazem and others): additive negative effects on AV conduction
- Drugs affecting potassium/electrolyte balance (diuretics, amphotericin B, glucocorticoids, laxatives, glucagon, high-dose IV dextrose, dextrose/insulin infusions, furosemide, thiazides): HYPOKALAEMIA predisposes to digoxin toxicity — this is the commonest real-world precipitant
- Spironolactone: may either enhance or decrease the toxic effects of digoxin
- Thyroid supplements: patients started on thyroid replacement may need their digoxin dose adjusted

## Pregnancy and lactation

Crosses the placenta; use only if clearly needed and monitor levels.

## Monitoring

- Serum digoxin 0.8–1.5 ng/mL, drawn 8–12 h post-dose, ~5–7 days after starting / changing dose
- Serum potassium (hypokalaemia potentiates toxicity)
- Renal function
- ECG for new arrhythmias; appetite (anorexia = early toxicity)

## Toxicity and overdose

Plumb's p.402: in dogs the acute toxic dose after IV administration is reported as 0.177 mg/kg. Treatment of CHRONIC toxicity is dictated by severity — many patients do well simply by temporarily stopping the drug and re-evaluating the dose regimen. For a recent acute ingestion with no cardiotoxic or neurologic signs yet (coma, seizures), empty the stomach and give activated charcoal; because digoxin is slowly absorbed and undergoes ENTEROHEPATIC RECIRCULATION, repeated charcoal doses are indicated. Correct hypokalaemia, which both provokes and worsens toxicity. Note for ECG interpretation: digoxin itself causes PR prolongation and ST-segment depression, and produces false-positive ST-T changes — do not read these as new ischaemia.

## Clinical pearls

- Anorexia / vomiting in a digitalised patient is toxicity until proven otherwise — stop the drug and check a level + potassium
- Correct hypokalaemia first — low potassium dramatically increases digoxin toxicity
- Skip loading doses; reaching steady state with maintenance dosing avoids most toxicity

## Mechanism of action

Plumb's pp.400–401: cardiac (digitalis) glycoside. Inhibits the sarcolemmal Na+/K+-ATPase, raising intracellular sodium and, via Na+/Ca2+ exchange, intracellular calcium — the basis of the positive inotropy. In a failing heart the net effects are increased myocardial contractility with increased cardiac output; increased diuresis with reduction of oedema secondary to decreased sympathetic tone; reduction in heart size, heart rate, blood volume and pulmonary and venous pressures; and usually NO net change in myocardial oxygen demand. It also has direct and vagally-mediated electrophysiological effects that slow AV conduction — which is why its clearest modern indication is rate control in atrial fibrillation rather than inotropic support. Plumb's is explicit that many cardiologists no longer consider digoxin first-line for heart failure, particularly since pimobendan became available, and that digoxin alone is rarely if ever used for heart failure.

## Formulations and products

- Digoxin 0.0625 mg tablet
- Digoxin 0.25 mg tablet
- Digoxin 0.05 mg/mL elixir

## Before you use this dose

> **Caution:** Reference doses for veterinary professionals. Confirm the dose against the product label, the patient’s condition, current guidance and local regulations before use; the attending veterinarian remains responsible for every clinical decision.

## Other cardiovascular drugs

- [Atenolol](https://vetmasterji.com/drugs/atenolol)
- [Benazepril](https://vetmasterji.com/drugs/benazepril)
- [Captopril](https://vetmasterji.com/drugs/captopril)
- [Carvedilol](https://vetmasterji.com/drugs/carvedilol)
- [Diltiazem](https://vetmasterji.com/drugs/diltiazem)
- [Dobutamine](https://vetmasterji.com/drugs/dobutamine)
- [Dopamine](https://vetmasterji.com/drugs/dopamine)
- [Enalapril](https://vetmasterji.com/drugs/enalapril)

## Frequently asked questions

### What is the dose of Digoxin for dogs?

Reference doses for Digoxin in dogs: 0.003–0.005 mg/kg PO q12h (AF rate control / CHF (oral maintenance)); 0.0055–0.011 mg/kg IV q1h to effect (Rapid digitalization (IV — inpatient only)). Confirm against the label and the patient before use.

### What is the dose of Digoxin for cats?

Reference doses for Digoxin in cats: 0.007–0.01 mg/kg PO q48h (DCM / advanced AV-valve disease (not HCM)). Confirm against the label and the patient before use.

### What is the dose of Digoxin for horses?

Reference doses for Digoxin in horses: 0.011–0.015 mg/kg PO q12h (Atrial fibrillation rate control / CHF); 0.002–0.0022 mg/kg IV q12h (IV maintenance). Confirm against the label and the patient before use.

### When should Digoxin not be used?

Ventricular arrhythmias, AV block, hypertrophic cardiomyopathy with outflow obstruction, hypokalaemia, significant renal impairment (renal excretion). Avoid loading doses.

### What are the side effects of Digoxin in animals?

Anorexia, vomiting, diarrhoea — often the FIRST signs of toxicity; Arrhythmias of any type — AV block, VPCs, bradycardia; Lethargy, depression.

## Sources

- Plumb's Veterinary Drug Handbook
- Papich, Papich Handbook of Veterinary Drugs, 5th edition

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VetMasterJi is a clinical decision-support and education platform for veterinary professionals and students. It does not provide veterinary advice, diagnosis or treatment for specific animals. All drug doses, calculators and differentials are references that must be independently verified before clinical use; the attending registered veterinarian remains solely responsible for every clinical decision.